What exactly does Cloud Mario do? He can create a mini-staircase out of happy clouds. Cloud Mario can make up to three cloud platforms.
Mario also has a planet turned spaceship, Starship Mario, which is unlocked after completing the first level. Once you jump into Starship Mario you can fly around a map, that takes inspiration from classic Mario games. As you play through Super Mario Galaxy 2, Starship Mario gains new features and picks up inhabitants.
A Luma is one friend that follows Mario around. When a friend picks up a remote they can control the Luma in Co-Star mode. Luma can grab enemies, stun nuisances with a spin move, and pick up coins. That’s a lot more than the star shooting second player option in the previous game.